Abstract: Objective To investigate the effects of Oxytocin(OT) on hippocampal long-term potentiation(LTP) and Fos protein expression which induced by peripheral stimulation. Methods Single stimulation pulses were delivered to the left sciatic nerves to evoke the field excitatory postsynaptic potentials (fEPSPs) in the right hippocampal CA1. Tetanic stimulation were used to induce hippocampal LTP. Different groups of rats were given NS, OT, Oxytocin antagonist- Atosiban + OT before tetanic stimulation, into lateral ventricle(LV) respectively. Expression of Fos protein were compared among the groups by histopathological and immunohistochemistry. Results Single stimulation evoked fEPSPs in hippocampal CA1, which average latency was 171.9±33.1ms and average amplitude was 25.7±8.4μV. Tetanic stimulation induced hippocampal LTP and increased the expression of Fos protein. Intracerebroventricular injection of OT inhibited hippocampal LTP and decreased the expression of Fos protein. This effect of OT was blocked by the pretreatment with Atosiban. Conclusions The results suggested that OT may play an inhibitory role in leaning and memory of rats; the effect is mediated by OT receptor.